The invention relates to a gas bag.
In the case of activation, a gas bag as part of an airbag module for a vehicle serves to slow down a vehicle occupant or a body part of the vehicle occupant. In the case of activation, the gas bag therefor is filled with gas by a gas generator, in order to provide a cushion-like protection for the vehicle occupant. For example, airbag modules are known which during a side impact of the vehicle serve to protect the head and thorax region of the vehicle occupant. In the properly arranged condition of such airbag module the gas-filled gas bag extends laterally beside the vehicle occupant in the case of activation. For a so-called far-side impact airbag modules are known, which are provided in the backrest of the vehicle seat on the side of the vehicle seat facing the vehicle center. In the case of activation, the gas-filled gas bag exits from the backrest on the side facing the vehicle center and slides between the vehicle occupant and the point of impact and in particular between the vehicle occupant and a possible adjacent vehicle occupant. For protection against a so-called near-side impact an airbag module with a gas bag is known, which in the case of activation extends like a curtain out of the ceiling of the vehicle body laterally beside the vehicle occupant.
To provide for a protection as efficient as possible, it is advantageous when the gas-filled gas bag is positioned relatively close to the head of the vehicle occupant. For this purpose, a gas bag chamber can be provided, which as compared to known gas bag chambers has a larger volume, so that in the case of activation it extends very close to the head of the vehicle occupant and can support the head and thorax region at an early stage. However, such gas bag would require more space than a known gas bag also in the folded condition. In addition, a comparatively larger gas generator is required, in order to be able to fill the large volume with gas. Consequently, the available installation space for the airbag module might be too small.
Another possibility of positioning the filled gas bag as close as possible to the head of the vehicle occupant consists in providing a gas bag which in the inflated condition is curved towards the vehicle occupant. For example, a curvature of the gas bag can be achieved by using additional catch straps attached to the gas bag layers of the gas bag, as is known for example from DE 44 05 927 A1. Alternatively, gathering seams in the gas bag layers can influence the shape of the gas bag in the inflated condition. This effect is utilized for example for the side airbag module known from EP 0 988 185 B1 and for the gas bag from EP 0 773 144 B1. Furthermore, a curvature of the inflated gas bag can be effected by using special blanks of the gas bag layers forming the gas bag. These measures however represent an additional expenditure in the development and manufacture of the gas bag.